The use of fiber reinforced polymer (FRP) is effective for strengthening existing reinforced concrete (RC) members in bending, shear, and axial confinement. This technique has been satisfactorily applied also to strengthen existing RC beam-column joints. However, limited research dealt with retrofitting severely damaged joints, and further research on the topic is needed. In this study, two exterior RC beam-column joints, that were damaged under quasi-static cyclic lateral loading, were repaired with externally bonded carbon-FRP composite and then retested. The columns of the specimens were strengthened by means of FRP strips applied on their surfaces, that were later covered by additional FRP sheets placed around them. This solution aims to confine the columns and provide anchorage to the longitudinal FRP sheets. In addition, two different configurations were used to strengthen the panel joints. In one specimen, additional horizontal FRP sheets were applied onto the panel joint surfaces and extended into the beam. In the remaining joint, the FRP sheets were placed aligned with the direction of the expected shear stresses. The response of the original and repaired specimens was evaluated and compared in terms of load-displacement hysteretic behavior, ultimate strength, stiffness decay, ductility, and energy dissipation
Experimental Behavior of Damaged RC Beam-column Joints Repaired with FRP Composites
Faleschini Flora;Gonzalez-Libreros Jaime;Zanini Mariano Angelo;Zampieri Paolo;Pellegrino Carlo
2017
Abstract
The use of fiber reinforced polymer (FRP) is effective for strengthening existing reinforced concrete (RC) members in bending, shear, and axial confinement. This technique has been satisfactorily applied also to strengthen existing RC beam-column joints. However, limited research dealt with retrofitting severely damaged joints, and further research on the topic is needed. In this study, two exterior RC beam-column joints, that were damaged under quasi-static cyclic lateral loading, were repaired with externally bonded carbon-FRP composite and then retested. The columns of the specimens were strengthened by means of FRP strips applied on their surfaces, that were later covered by additional FRP sheets placed around them. This solution aims to confine the columns and provide anchorage to the longitudinal FRP sheets. In addition, two different configurations were used to strengthen the panel joints. In one specimen, additional horizontal FRP sheets were applied onto the panel joint surfaces and extended into the beam. In the remaining joint, the FRP sheets were placed aligned with the direction of the expected shear stresses. The response of the original and repaired specimens was evaluated and compared in terms of load-displacement hysteretic behavior, ultimate strength, stiffness decay, ductility, and energy dissipation
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